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The combined heating method of seat heating and air conditioning (A/C) was applied in the passenger compartment under different experiment conditions, using thermocouples to continuously measure the wall surfaces and air temperatures in the passenger compartment and the passengers' skin temperatures of 17 segments. Meanwhile, a subjective evaluation questionnaire survey was conducted using a nine-point evaluation scale on the local and overall thermal sensation and thermal comfort of the passengers, and the data from the questionnaire were analyzed with the ANOVA method. The results showed that the use of the heating pad directly affected the changes in human skin temperature, which in turn affected the local and overall thermal sensation and thermal comfort. For the two thermally stimulated segments of the back and under the thighs, the skin temperature of the back was higher than that of the thighs. Using the heating pad resulted in a rapid increase in the mean skin temperature in the early period of the experiment. Thermal sensation of the back and under-thighs shifted rapidly towards the hot zone in the first 10 min, and then settled around +3, with even more significant differences between the groups. Thermal sensations in non-thermally stimulated segments changed in relation to their position on the heating pad, with slower changes in those at the "distal" end of the body, the head and the feet. Continued use of the heating pads at lower ambient temperatures maintained overall thermal comfort at a neutral level in the range of 0–1, whereas at higher ambient temperatures there was a gradual deterioration of local and overall thermal comfort. [ABSTRACT FROM AUTHOR]

There have been fruitful publications on thermal comfort of urban residential buildings in China. However, there is a lack of reviews on this topic to perform a comprehensive analysis and find opportunities to meet occupants' thermal comfort needs while improving building energy efficiencies. This paper addresses this issue by presenting a systematic review on the advancements in research on thermal comfort in urban residential buildings in China. Firstly, two common thermal comfort research approaches, i.e., field studies and laboratory studies, are discussed. Secondly, eleven main thermal comfort evaluation indicators are summarized. Finally, this paper analyzes the thermal comfort survey data from different researchers, discusses the impacts of adaptive behaviors on human thermal comfort, and provides recommendations for future research on urban residential thermal comfort. It was found that people have higher and higher requirements for their indoor thermal environment as time goes by, especially in the winter; the thermoneutral temperature is higher in warmer climate regions in the summer but lower in the winter than in colder climate regions; the thermoneutral temperature tends to increase with the indoor air temperature due to an adaptation to the indoor thermal environment. The outcomes of this paper provide valuable information on thermal comfort behaviors of urban residents in different climate zones in China, which can serve as a resource for the academic community conducting future research on thermal comfort and assist policymakers in enhancing building energy efficiencies without compromising the occupants' comfort. [ABSTRACT FROM AUTHOR]

High outdoor temperatures and thermal gains due to solar radiation, which penetrates the interior of buildings as the climate warms up, pose a major challenge to maintaining thermal comfort in passive sports facilities. Superbly insulated and airtight envelopes, specific microclimatic requirements and very high user activity can easily lead to overheating and thermal imbalance during summer. This paper focuses on the influence of the varying thermal capacity of external walls and night-time cooling on thermal comfort in a passive sports hall building. Based on experimental studies of the thermal conditions in the building, a model of it was created in Design Builder. Through simulation, the program initially analysed the thermal conditions that arise under different envelope assemblies. Two different ways of cooling the building at night were then analysed: mechanical and natural. The results presented showed that in a well-insulated sports hall with a large volume, the type of wall material alone had only a limited influence on thermal comfort in summer. In contrast, night-time cooling in integration with the accumulation of cold in the building's structural components had a significant impact on protection against overheating during the summer. The type of envelope material is even more important when night-time air exchange is high. Intensive natural ventilation is associated with the highest number of hours in the comfort range—28.1–32.4% more hours in relation to the variant without night ventilation. The use of mechanical ventilation, operating at night at maximum capacity, will result in an increase in the number of hours with air temperatures in the −0.5 < PMV < +0.5 range by only 14.1–21.3%. The high thermal mass of the envelope, combined with adequate ventilation, reduces the occurrence of very high indoor air temperatures, thus alleviating the nuisance of overheating. The maximum internal air temperature during the day is lower by 2.4–3.3 K, compared to the case when no night ventilation is used. Mechanical ventilation operating at its maximum capacity can reduce the maximum internal temperature by 1.2–1.6 K. [ABSTRACT FROM AUTHOR]

The standard for ergonomics of the thermal environment provides information on the calculation of optimal thermal comfort. Operative temperature (OT) is one of the essential elements of thermal comfort and is a function of air temperature, mean radiant temperature (MRT), and air velocity. This paper investigates the impact of diverse influences on MRT in an office room based on occupant position and posture (seated and standing). A comparative simulation study of the varied thermal transmittance (U-value) of the only external wall with a window in an office room depending on the wide-ranging outdoor temperature is conducted in the MATLAB tool Simulink. The air temperature and air velocity are assumed according to the standards, and the MRT is simulated. The angle factors, U-value of walls/windows, occupant position, occupant posture, and outdoor temperature are the critical parameters that affect MRT. The results show varied responses from MRT for each of the five outdoor temperature scenarios simulated for three types of exterior walls. Seated occupants have equal MRT, whereas standing occupants have minor discrepancies when exposed to a window at the same distance in all outdoor scenarios. When the placement of occupants is not equally exposed to the window, the seated occupants have a higher MRT difference than the standing occupants. [ABSTRACT FROM AUTHOR]

Upgrades in building energy efficiency codes led to differences between buildings designed according to outdated codes and those with most recent requirements. In this context, our study investigates the influence of external wall thermal transmittance, thermal inertia, and orientation on energy demand (heating, cooling) and occupant thermal comfort. Simulation models of an office building were designed, varying (i) the thermal transmittance values (0.20 and 0.60 W/(m2K)), (ii) the room orientation (four cardinal directions), and (iii) the wall thermal inertia (approximately 60 kJ/(m2K) for low and 340 kJ/(m2K) for high thermal inertia. The energy demand for heating and cooling seasons was calculated for Ljubljana using EnergyPlus 9.0.0 software. The reduction of the external wall thermal transmittance value from 0.6 W/(m2K) to 0.2 W/(m2K) contributes to significant energy savings (63% for heating and 37% for cooling). Thermal inertia showed considerable potential for energy savings, especially in the cooling season (20% and 13%, depending on the external wall insulation level). In addition, the orientation proved to have a notable impact on heating and cooling demand, however not as pronounced as thermal inertia (up to 7% total energy demand). Comparison of the thermal comfort results showed that when internal air temperatures are identically controlled in all the rooms (i.e., internal air temperature is not an influencing factor), the external wall thermal transmittance, thermal inertia, and room orientation show negligible influence on the average occupant thermal comfort. The simultaneous achievement of thermally comfortable conditions in the working environment and low energy use can only be achieved by simultaneously considering the U-value and thermal inertia. [ABSTRACT FROM AUTHOR]

Students require a comfortable thermal environment for better academic learning and health in general. In Nepal, the majority of school buildings are constructed using local materials, but little consideration is provided to the thermal environment required for comfort. Therefore, this study demonstrates the advantages of using passive design measures through a simulation that can be used either in the early stages or as a retrofit to determine how the building performs in terms of comfort and the thermal environment. First, the thermal environment of school buildings and thermal comfort of students were evaluated through field surveys. Subsequently, a simulation was performed to investigate the operative temperatures in the classroom of a school building in Kathmandu. DesignBuilder software was used to create the base model and the simulated operative temperature was validated using the measured globe temperature. Subsequently, passive strategies, such as natural ventilation, insulation, and thermal mass, were applied and analysed. The field survey showed that the indoor globe and outdoor air temperatures were correlated, and the students perceived a hotter environment and preferred a cooler environment. Within this context, the average comfort temperature was 26.9 °C. The simulation results showed that the operative temperature was reduced to below 27 °C with a maximum reduction of 3.3 °C due to the integrated design impact, which is within the comfortable limit required during school hours. This study helps to design Nepalese school buildings in a better way by considering passive design strategies during architectural design to make classrooms more thermally comfortable. [ABSTRACT FROM AUTHOR]

A suitable indoor climate positively affects the lifespan of historical building structures. The path to an agreeable climate begins with monitoring current conditions. Considerable attention is given to monitoring the indoor climate of historical buildings. The motivation for monitoring air temperature and surface temperatures, relative air humidity or airflow can be, for example, the installation of heating, the occurrence of biotic damage, and others. Through the analysis of the most frequently used keywords, a strong connection was found, for example, between thermal comfort and the church. This review also summarises the various reasons for conducting microclimate monitoring studies in historical religious buildings on the European continent. It is supplemented with an evaluation of the monitoring methodology from the chosen period of the year point of view, the measured parameters, and the length of the interval between the recordings of quantities. It was found that in more than one-third of the cases, the recording time was less than or equal to 15 min, but mostly less than or equal to 1 h. Quite often, monitoring results are used to calibrate a simulation model describing the hydrothermal behaviour of a historical object under various operation alternatives (e.g., influence of ventilation, climate change, occupancy, etc.). This way, it is possible to test various intelligent systems in the virtual world without much risk before they are used in an actual building application. [ABSTRACT FROM AUTHOR]

Comfort temperature is important to investigate because the chosen office indoor temperatures affect the energy used in a building, and a thermally comfortable environment makes the occupants be more productive. The effects of temperature on comfort are broadly recognized for thermal comfort. Japanese office buildings are well equipped with air-conditioning systems to improve the thermal comfort of the occupants. The main objectives of this research were to compare the winter comfort temperature in mixed mode (MM) and heating, ventilation and air-conditioning (HVAC) office buildings and to investigate the relationship between the comfort temperature and the indoor air temperature. This study measured the thermal environmental conditions of the office buildings and surveyed the thermal comfort of the occupants. The field survey was conducted during winter in seven office buildings located in the Aichi prefecture of Japan. In total, 4466 subjective votes were collected from 46 occupants. The result suggested that the occupants were found to be more satisfied with the thermal environment of MM buildings than that of HVAC office buildings. Overall, 95% of comfort temperatures were in the range 22~28 °C in MM and HVAC buildings, which were higher than the indoor temperature of 20 °C recommended by the Japanese government. The comfort temperature was highly correlated to the indoor air temperature of the MM buildings than to that of HVAC buildings. This indicated that the occupants were more adapted towards the given thermal environment of MM buildings. [ABSTRACT FROM AUTHOR]

Among the alternatives for improving the thermal comfort conditions inside buildings are the thermally activated building systems (TABS). They are embedded in different building components to improve the indoor air temperature. In this work, a review and analysis of the state of the art of TABS was carried out to identify their potential to improve thermal comfort conditions and provide energy savings. Furthermore, this study presents the gaps identified in the literature so that researchers can develop future studies on TABS. The articles found were classified and analyzed in four sections, considering their implementation in roofs, walls, floors, and the whole envelope. In addition, aspects related to the configuration of the TABS and the fluid (speed, temperature, and mass flow rate) were analyzed. It was found that when TABS are implemented in roofs, walls, and floors, a reduction in the indoor temperature of a building of up to 14.4 °C can be obtained. Within the limitations of the TABS, the complexity and costs of their implementation compared to the use of air conditioning systems are reported. However, the TABS can provide energy savings of up to 50%. [ABSTRACT FROM AUTHOR]

The Urban Heat Island (UHI) has a detrimental impact on human thermal comfort and the health of city dwellers through raising average temperatures. Urban geometry is one of the factors that affect the intensity of the UHI phenomena. The purpose of this research is to evaluate and compare traditional vs. modern urban forms with respect to temperature and thermal comfort in the United Arab Emirates. Three of each were chosen based on their densities and form. Traditional buildings in the UAE differ from others in the Middle East in that they are primarily single-story, while in the surrounding countries of the region, such as Iran, Iraq, and Saudi Arabia, they are mainly two stories. The UAE climate also has its distinct characteristics. Each configuration was investigated using the ENVI-met urban microclimate simulation software. The comparisons were made for three seasons: summer, winter, and spring. Each configuration was evaluated through four parameters: building shape, street geometry, orientation, and urban density. The results revealed that the low-density traditional urban form exhibited the lowest air temperature in August because it has a low sky view factor (SVF), high height-to-width ratio, and less density. The highest ambient temperature was observed in the sites with low-medium density, lowest height/width ratio, and maximum SVF. The high-density modern urban form displayed lower air temperatures in the summer season than the low and low-medium-density modern urban sites due to the building form, high height-to-width ratio, low SVF, and wind corridors. The traditional compact urban form in Al Fahidi, which has the highest urban density of the six configurations, achieved the best thermal comfort levels in the summer due to the sizable height-to-width ratio and lowest SVF. [ABSTRACT FROM AUTHOR]

There is growing concern that airtight and well-insulated buildings designed to limit heat loss in temperate and cold climates could unintentionally elevate the risk of overheating in summers. Existing literature primarily uses dynamic simulation to investigate this problem due to the difficulty of obtaining large-scale in-performance data. To address this gap, we undertake a meta-analysis of large-scale indoor air temperature data for 195 UK dwellings, as a study of performance in a temperate climate. Of these, 113 are baseline (i.e., typical existing dwellings) and the rest designed to the high-performance Passivhaus standard. Using both Passivhaus and the well-known CIBSE TM59 overheating standards, this study found that there were few overheated cases for any building type. However, the average summer nighttime temperature of Passivhaus bedrooms was 1.6 °C higher than baseline, with 20 out of 31 measured bedrooms exceeding the overheating criterion, and the average overheating hours constituting approximately 19% of the total summertime observation period. These findings suggest that bedrooms in highly insulated dwellings may pose an overheating risk although whole-dwelling overheating risk is low. [ABSTRACT FROM AUTHOR]

In warm and hot climates, ceiling fans and/or air conditioners (ACs) are used to maintain thermal comfort. Ceiling fans provide air movement near the skin, which enhances the evaporation of sweat, reduces heat stress, and enhances thermal comfort. This is also called the cooling effect. However, AC usage behaviour and the effects of elevated air speed through the use of ceiling fans on indoor operative temperature during AC usage are not widely studied. This study investigated the optimum AC (cooling) set point temperature and air velocity necessary for maintaining thermal comfort while achieving energy conservation, in mixed-mode buildings in India, through field studies by using used custom-built Internet of Things (IOT) devices. In the current study, the results indicate a 79% probability that comfort conditions can be maintained by achieving a temperature drop of 3K. If this drop can be achieved, as much as possible, through passive measures, the duration of AC operation and its energy consumption are reduced, at least by 67.5 and 58.4%, respectively. During the air-conditioned period, there is a possibility that the cooing effect is reduced because of increase in operative temperature due to ceiling fan operation. Therefore, the optimum solution is to maintain the highest AC set point and minimum fan speed setting that are acceptable. [ABSTRACT FROM AUTHOR]

It has been identified that improving building energy efficiency is an effective method to reduce greenhouse gas (GHG) emissions. Although standards have been established to satisfy a building's minimum energy demand while ensuring the comfort of its residents, they are difficult to implement in mixed-humid regions. This study proposes a hybrid ventilation strategy that can comprehensively reduce cooling, heating, and ventilation energy in mixed-humid climate regions to significantly decrease the primary energy demand and reduce the impact of buildings on the environment. This study evaluated the changes in energy saving potential and thermal comfort according to the extension of the natural ventilation period and passive strategies, such as decentralized ventilation. Changes in indoor air temperature, operative temperature, and PMV for each strategy were analyzed. As a result, extending the natural ventilation and the decentralized ventilation strategies can save 32% and 34% of the building's energy, respectively. Considering that electricity is the main energy source for cooling in Korea, the extension of the natural ventilation period was judged to be the best approach from the perspective of primary energy demand. The results can be used to predict changes in building energy demand and thermal comfort and select an appropriate ventilation strategy based on occupant information obtained using Internet of Things. [ABSTRACT FROM AUTHOR]

Passive thermal comfort has been widely used to test the thermal performance of a building. The science of active thermal comfort is important to be connected with the science of architecture. The currently developing active thermal comfort is adaptive thermal comfort. Vernacular houses are believed to be able to create thermal comfort for the inhabitants. The present study seeks to analyze the connection between the architectural elements of vernacular houses and adaptive thermal comfort. A mixed method was applied. A quantitative approach was used in the measurement of variables of climate, while a qualitative methodology was employed in an interview on thermal sensations. The connection between architectural elements and adaptive thermal comfort was analyzed by considering the correlation among architectural features, the analysis results of thermal comfort, and the Olgyay and psychrometric diagrams. At the beginning of the rainy season, residents of exposed stone houses had the highest comfortable percentage of 31%. In the middle of the rainy season, the highest percentage of comfort was obtained by residents of exposed brick and wooden houses on the beach at 39%. The lowest comfortable percentage experienced by residents of exposed stone houses at the beginning of the dry season was 0%. The beginning of the dry season in mountainous areas has air temperatures that are too low, making residents uncomfortable. The study results demonstrate that adaptive thermal comfort is related to using a room for adaptation to create thermal comfort for the inhabitants. [ABSTRACT FROM AUTHOR]

A good thermal environment is important in a place where occupants stay for a long time. Since heating a house consumes a lot of energy, an energy-efficient heating method will be required. Then, by combining a heat pump and underfloor heating, there is a possibility that both thermal comfort and energy saving can be achieved. The survey was conducted on a detached house located in Nagano Prefecture, Japan. The average outside air temperature was 4.2 °C. This study investigated the indoor thermal environment, evaluated the operating performance of the heat pump, and calculated the heat load by two-dimensional analysis. More than 80% of the subjects were satisfied with the thermal environment and the neutral temperature was 18.9 °C. In the operation of the heat pump, defrost operation was confirmed, but the average COP was 2.9, and it operated efficiently. In addition, the heat loss from the foundation slab was examined. Proper insulation placement has shown the potential to reduce heat loss. In conclusion, the use of heat pumps as a heat source has been shown to be efficient even in cold climates, and this study supports the construction of new heating methods. [ABSTRACT FROM AUTHOR]

Over the past decades, Southern European residential architecture has been typically associated with heavyweight hollow brick masonry and reinforced concrete construction systems; however, more industrialised alternative systems have been gaining a significant market share, such as the light steel framing (LSF). Regardless of the proliferation of LSF buildings, a lack of experimental research studies have been performed on this construction system in terms of the indoor thermal environment and thermal comfort in the Southern European climate context. Moreover, a research gap also exists regarding experimental comparisons with typical brick masonry buildings. The present study focused on this research gap by characterising and comparing the performance of these two construction systems. A long-term experimental campaign was carried out, involving the construction and monitoring of two identical test cells, differing only by construction system. The test cells were located in Portugal and were monitored over an entire year. The results revealed that the LSF experimental test cell presented higher daily indoor air temperature fluctuations, leading to more extreme maximum and minimum values, closely following the outdoor dry bulb temperature variations. The more responsive behaviour was also reflected in the indoor thermal comfort analysis, with the LSF cell presenting slightly worse performance; however, some advantages were also observed regarding the LSF construction system, which could provide benefits during intermittent residential occupation, especially in mild climates, in which overheating is not a major concern. [ABSTRACT FROM AUTHOR]

This work describes the design, construction and testing of a thermo-electric conditioning device installed in a neonatal incubator with the aim of improving the precision in the regulation of the interior air temperature, reducing noise and interior vibration, and improving the life of the neonate. A simplified one-dimensional thermal model has been developed, made up of resistances and thermal capacities that simulate the thermal behaviour of all the elements of the system from end to end. All the equations of the model are obtained in a nodal way, allowing the mathematical relationship between the input and output to be known. This model makes it possible to improve temperature control, avoiding the deviations that occur in the traditional model controlled by sensors at both ends. The computational model allows to predict the variation of temperatures in transient and permanent regime. This model allows the design and sizing of the thermoelectric system for different outdoor environmental conditions and the selection of the number of Peltier modules needed to satisfy the heating demand of other incubators with different geometry and capacity. The results of the computational model show good agreement with the experimental tests, despite being a simplified 1D nodal model. The results obtained show a coefficient of operation (COP) of 1.38, achieving higher performance than the current traditional electrical resistance system (COP = 1). In addition, a CFD study has been carried out to check the air patterns, to see the temperature uniformity and to estimate the number of air changes per hour (HVAC) inside the incubator. [ABSTRACT FROM AUTHOR]

This paper investigates adaptive thermal comfort during summer in medical residences that are located in the French city of Troyes and managed by the Association of Parents of Disabled Children (APEI). Thermal comfort in these buildings is evaluated using subjective measurements and objective physical parameters. The thermal sensations of respondents were determined by questionnaires, while thermal comfort was estimated using the predicted mean vote (PMV) model. Indoor environmental parameters (relative humidity, mean radiant temperature, air temperature, and air velocity) were measured using a thermal environment sensor during the summer period in July and August 2018. A good correlation was found between operative temperature, mean radiant temperature, and PMV. The neutral temperature was determined by linear regression analysis of the operative temperature and Fanger's PMV model. The obtained neutral temperature is 23.7 °C. Based on the datasets and questionnaires, the adaptive coefficient α representing patients' capacity to adapt to heat was found to be 1.261. A strong correlation was also observed between the sequential thermal index n (t) and the adaptive temperature. Finally, a new empirical model of adaptive temperature was developed using the data collected from a longitudinal survey in four residential buildings of APEI in summer, and the obtained adaptive temperature is 25.0 °C with upper and lower limits of 24.7 °C and 25.4 °C. [ABSTRACT FROM AUTHOR]

In order to reduce the energy consumption of HVAC systems in buildings, the use of energy-saving solutions is necessary. One of these solutions is ventilation, which is usually used for maintaining acceptable indoor air quality and thermal comfort. As the change in outdoor environment is unpredictable and the occupant control is spontaneous, it is critical to control the windows and HVAC systems to achieve a maximum use of outdoor air for indoor ventilation. A new rule-based control strategy that could change the opening factor of windows is proposed in this study and its effectiveness was tested in five representative climates, ranging from a subtropical region to a severely cold region. A building model was set up and the indoor air temperature and energy consumption were predicted using EnergyPlus. The results show that the proposed control strategy can utilize ventilation to maintain a comfortable indoor environment with an annual uncomfortable percentage in an occupied period lower than 5%, thus leading to an energy-saving rate of 13.5–55.6%. The simulation results indicate that there are periods of ventilation available during the summer in climate zones with hot summers and warm winters, whereas the control strategy has a better energy-saving performance in temperate areas. This study conducted a preliminary exploration for practical applications of the combined operation of controllable natural ventilation and HVAC systems in buildings. [ABSTRACT FROM AUTHOR]

Modern buildings with new heating, ventilation and air conditioning (HVAC) systems offer possibility to fit parameters of the indoor environment to the occupants' requirements. The present paper describes the results of measurements performed in an office room in the first Polish passive commercial office building during four months of normal operation. They were used to calculate parameters describing thermal comfort: vertical air temperature profile, floor surface temperature, predicted mean vote (PMV) and predicted percent of dissatisfied (PPD). Obtained results confirmed good thermal conditions in the analysed room. The average temperature of the floor's surface varied from 20.6 °C to 26.2 °C. The average vertical air temperature, calculated for working days, was from 22.5 °C to 23.1 °C. The temperature difference between the floor and 5 cm below the ceiling was from −0.9 °C to 6.3 °C. The PMV index varied from 0.52 to 1.50 indicating 'slightly warm' sensation, in spite of 'neutral' reported by employees. Also measured cooling and heating energy consumption was presented. The performed measurements confirmed the ability of thermally activated building system (TABS) to keep good thermal conditions. [ABSTRACT FROM AUTHOR]

This paper reviewed related research works and developments on the traditional architectural element "mashrabiya" focusing on its history, design and structure, typology, and functions in hot climates. Moreover, the paper assessed the effect of the traditional mashrabiya on the indoor thermal environment and thermal comfort in a selected case study building. For this purpose, two similar rooms were investigated in a selected historic building with abundant mashrabiyas located in the Makkah Region, specifically in Old Jeddah, Saudi Arabia. The field tests were conducted during a typical hot summer month with two different configurations. The study demonstrated that opening the mashrabiya allowed more airflow into the room during the day and reduced the indoor temperature by up to 2.4 °C as compared to the closed mashrabiya. Besides, the building envelope played an important role in preventing the high fluctuation of the indoor air temperature, where the fluctuation of the rooms air temperature ranged between 2.1 °C and 4.2 °C compared to the outdoor temperature which recorded a fluctuation between 9.4 °C and 16 °C. The data presented here can be used for the future development of the mashrabiya concept and the potential incorporation with passive cooling methods to improve its design according to the requirements of modern buildings in hot climates. Moreover, further studies and tests on mashrabiyas under different climatic conditions are required. Also, the different strategies or materials can be incorporated with mashrabiyas in order to improve its thermal performance. [ABSTRACT FROM AUTHOR]

Ceiling radiant cooling panel (CRCP) systems are being increasingly applied to commercial buildings due to their high thermal comfort level and energy efficiency. It is recommended that CRCP systems should be operated at a relatively high chilled water temperature to prevent condensation and save energy. However, even though a high chilled water temperature is effective for achieving condensation-free operation and high chiller efficiency, it can lead to insufficient cooling capacity. In this study, a method of enhancing the cooling capacity of CRCP systems was investigated through mock-up chamber tests. The open-type installation of CRCPs and the combination of air circulators were used to enhance the cooling capacity and energy performance of CRCP systems. Experimental results showed that compared to a conventional CRCP system, the cooling capacity of an open-type CRCP system with air circulators increased by up to 26.2%, and its cooling energy consumption decreased by up to 26.4%. Additionally, the open-type CRCP system with air circulators reduced the difference between the room air temperature and mean chilled water temperature. Thus, the proposed system can operate at a relatively high chilled water temperature, which is effective for reducing condensation risk and cooling energy consumption. [ABSTRACT FROM AUTHOR]

Changing climatic conditions cause the variability of the parameters of the building's surroundings, which in turn causes both the gains and losses of heat to change over time. There is variability in both daily and annual cycles. Meeting the requirements of thermal comfort in rooms requires maintaining the required parameters, including constant temperature. Heat gains and losses must be balanced, and this balance is ensured through appropriate heating systems. At the same time, the above means that the demand for heating buildings is not constant but depends on external weather conditions and the energy efficiency of the building. This, in turn, affects the thermal inertia, causing changes in the partition temperature to occur slower than the changes in air temperature. Therefore, the amplitude of the heating power changes is not proportional to the amplitude of the outside air temperature change. The paper presents an example of the analysis of thermal dynamics in buildings. Various aspects of heat transfer in the building were investigated taking into account the transient conditions. The variability of temperature over time at different depths of the partition was analysed, showing the results graphically. The periodic variability of the outside air temperature and the intensity of solar radiation were described by the Fourier series. Moreover, the article shows the influence of the thermal insulation thickness of the external wall on the annual amplitude of temperature changes and on the duration of the heating season, which is important from the point of view of optimization. [ABSTRACT FROM AUTHOR]

The influence of emitters, heat pump size and building envelope thermal inertia was investigated on the energy consumption of a heat pump-based heating system with a numerical study performed with the dynamic software TRNSYS. An algorithm based on a Thermal Inertia Control Logic (TICL), which can exploit the capability of the building envelope to store thermal energy, has been applied. When the proposed algorithm is employed, the indoor air temperature set-point is increased when the outdoor temperature is larger than the bivalent temperature of the building-heat pump system. Different configurations of the heating system were simulated considering either convective (fan-coil) or radiant (radiant floor) emitters coupled to a variable-speed air-to-water heat pump. Simulations have been carried out considering a reference building derived from the IEA SHC Task 44 and evaluating the influence of the proposed control logic on both the heat pump seasonal energy performance and the internal comfort conditions perceived by the building users. The obtained results highlight how the introduced TICL can guarantee the use of downsized heat pumps, coupled to radiant emitters, with a significant enhancement of the seasonal performance factor up to 10% and a slight improvement of comfort conditions. On the other hand, when convective terminal units are considered the proposed logic is not effective and the overall energy consumption of the system increases up to 15%. [ABSTRACT FROM AUTHOR]

As most residents spend more than 90% of their time in buildings, acceptable and reasonable control of both indoor thermal comfort and air quality is imperative to ensure occupants' health status and work productivity. However, current control strategies generally take either thermal comfort or indoor air quality as a single loop, rather than the concurrent control of two. To analyze their mutual influence, this study investigated the performance of three multi-control approaches, i.e., proportional integral derivative (PID) control of thermal comfort and a fixed outdoor air ratio, PID control of thermal comfort and design outdoor air rate, and PID control of thermal comfort and occupancy-based demand-controlled ventilation. As a pilot study, three typical control methods were implemented to a multi-zone building via OpenModelica modeling. The results indicate that indoor air temperature can be well-maintained under three control methods, however, the CO2 concentration under the fixed outdoor air ratio was over 1000 ppm, leading to poor indoor air quality. The control strategy with the design outdoor air rate could not properly ensure the CO2 concentration, due to the over-ventilated or under-ventilated phenomena, subsequently resulting in unnecessary energy waste. The occupancy-based demand controlled ventilation could maintain the CO2 concentration under the set-point with an intermediate power energy utilization. [ABSTRACT FROM AUTHOR]

A simplified algorithm using an artificial neural network (ANN, a feed-forward neural network) for the assessment of the predicted mean vote (PMV) index in summertime was developed, using solely three input variables (namely the indoor air temperature, relative humidity, and clothing insulation), whilst low air speed (<0.1 m/s), a minimal variation of radiant temperature (25.1 °C ± 2 °C) and steady metabolism (1.2 Met) were considered. Sensitivity analysis to the number of variables and to the number of neurons were performed. The developed ANN was then compared with three proven methods used for thermal comfort prediction: (i) the International Standard; (ii) the Rohles model; (iii) the modified Rohles model. Finally, another network able to predict the indoor thermal conditions was considered: the combined calculation of the two networks was tested for the PMV prediction. The proposed algorithm allows one to better approximate the PMV index than the other models (mean error of ANN predominantly in ±0.10–±0.20 range). The accuracy of the network in PMV prediction increases when air temperature and relative humidity values fall into 21–28 °C and 30–75% ranges. When the PMV is predicted by using the combined calculation (i.e., by using the two networks), the same order of magnitude of error was found, confirming the reliability of the networks. The developed ANN could be considered as an alternative method for the simplified prediction of PMV; moreover, the new simplified algorithm can be useful in buildings' design phase, i.e., in those cases where experimental data are not available. [ABSTRACT FROM AUTHOR]

The thermal sensations of people differ from each other, even if they are in the same thermal conditions. The research was carried out in a didactic teaching room located in the building of the Faculty of Civil and Environmental Engineering in Poland. Tests on the temperature were carried out simultaneously with questionnaire surveys. The purpose of the survey was to define sensations regarding the thermal comfort of people in the same room, in different conditions of internal and external temperatures. In total 333 questionnaires were analyzed. After the discriminant and neural analyses it was found that it is not possible to forecast the thermal comfort assessment in the room based on the analyzed variables: gender, indoor air temperature, external wall radiant temperature, and outdoor air temperature. The thermal comfort assessments of men and women were similar and overlapped. The results of this study confirm that under the same thermal conditions about 85% of respondents assess thermal comfort as good, and about 15% of respondents assess thermal comfort as bad. The test results presented in this article are similar to the results of tests carried out by other authors in other climatic conditions. [ABSTRACT FROM AUTHOR]

Improving the energy efficiency of buildings is among the most urgent social development tasks due to the scale of energy consumption in this industry. At the same time, it is essential to meet high requirements for indoor environmental quality and thermal comfort. The issue of overheating is most often analysed in summer but it also occurs in transition seasons, when the cooling systems do not operate. The paper attempts to evaluate the effectiveness of external mobile shading elements on the microclimate of rooms with large glazed areas in the transition season. Passive solutions, such as shading elements, which limit the increase of indoor temperature, do not always allow the acquisition and maintenance of comfortable solutions for the duration of the season, as demonstrated by the authors. Temporary cooling of the rooms may be necessary to maintain comfortable conditions for the users, or other solutions should be devised to improve comfort (e.g., reduction of clothing insulation characteristics). The novelty of the study consists in the analysis of comfort in a "nearly zero energy consumption" building (NZEB) during a period not analyzed by other scientists. This is a transition period during which heating/cooling systems do not operate. The research task set by the authors involved the assessment of the possibility to reduce office space overheating in the transition season (spring) by using external shading equipment in rooms with large glazed areas. An additional research task aimed at checking the extent to which user behaviour, such as reduction in clothing insulation characteristics, can improve comfort in overheated rooms. The results of the tests reveal that the difference in the ambient air temperature between a room with external venetian blinds and an identical room with no venetian blinds in the transition season, i.e., from 27 March to 6 April 2017, ranged from 12.3 to 2.1 °C. The use of a shading system (external venetian blinds positioned at an angle of 45°) reduced the number of discomfort hours by 92% (during working hours) compared to the room without external venetian blinds. A reduction in the thermal insulation of the clothes worn by people working in the room with no venetian blinds helped to reduce the number of discomfort hours by 31%. [ABSTRACT FROM AUTHOR]

This empirical study investigates large urban park cooling effects on the thermal comfort of occupants in the vicinity of the main central park, located in Madrid, Spain. Data were gathered during hot summer days, using mobile observations and a questionnaire. The results showed that the cooling effect of this urban park of 125 ha area at a distance of 150 m could reduce air temperatures by an average of 0.63 °C and 1.28 °C for distances of 380 m and 665 meters from the park. Moreover, the degree of the physiological equivalent temperature (PET) index at a distance of 150 meters from the park is on average 2 °C PET and 2.3 °C PET less compared to distances of 380 m and 665 m, respectively. Considering the distance from the park, the correlation between occupant perceived thermal comfort (PTC) and PET is inverse. That is, augmenting the distance from the park increases PET, while the extent of PTC reduces accordingly. The correlation between these two factors at the nearest and furthest distances from the park is meaningful (p-value < 0.05). The results also showed that large-scale urban parks generally play a significant part in creating a cognitive state of high-perceived thermal comfort spaces for residents. [ABSTRACT FROM AUTHOR]

Thermal comfort is an important aspect to take into consideration for the indoor environment of a building integrated with a semi-transparent Photovoltaics (STPV) system. The thermal comfort of units with photovoltaic windows and that of conventional windows, which is an ordinary without PV, were evaluated via on-site tests and questionnaires. Using the thermal comfort investigation of the test rig, the maximum difference in air temperature was found to be around 5 °C between test unit and comparison unit. The predicted mean vote (PMV)–predicted percentage dissatisfied (PPD) value of the test unit was better than that of the comparison unit. It was observed that on sunny days, the PMV value ranged from 0.2 (nature) to 1.3 (slightly warm) in the test unit, and that of the comparison unit was 0.7 (slightly warm) to 2.0 (warm), thereby providing better thermal comfort, especially during mornings. The maximum difference in PPD values was found to reach 27% between the two units at noon. On cloudy days, the difference was negligible, and the thermal sensation between the foot and the head were almost the same. Fifty respondents were asked to complete a carefully designed questionnaire. The thermal sensation of the test unit was better than that of comparison unit, which corresponded with the test results. Thermal, lighting, acoustic, and other environment comfort scores were combined, and the acceptance of the test unit with the STPV windows was found to be 73.8%. The thermal sensation difference between men and women was around 5%. Thus, during summer, STPV windows can improve the thermal comfort and potentially reduce the air-conditioning load. [ABSTRACT FROM AUTHOR]

The relatively low thermal mass of timber frame buildings is a limiting factor for their energy efficiency and for the thermal comfort. The aim of this study is to assess the performance of wood-based wallboards integrated with PCM (Phase Change Materials) in a cold climate (Québec, Canada), from the heating season to the summer. Two timber-frame test huts, of 2 × 2.5 × 3 m, were built following the National Building Code of Canada and placed in the LAVAL University Campus. The first hut was equipped with wood-based panels integrated with the commercial bio-based PCM Puretemp®23 with a 23 °C melting point. The second hut was equipped with standard interior wood panels. Large double glaze windows were installed facing south. Dry indoor air temperatures were recorded for both huts and for the heating season, heating consumptions were monitored. The behaviour of the two huts was compared and PCM panels efficiency was evaluated over several seasons. A reduction of heating consumption was observed for cold months. For the heating season, panels were found to be more efficient as the months were getting milder. By gathering solar energy during the day, they allowed to reduce the test-hut heating consumption, by a maximum of 41% in May. In summer, the PCM panels had a positive impact in order to reduce the hut overheating. However their efficiency was found limited by a poor ability of discharge during the night. The solidification of the PCM was often impossible to achieve due to unsuitable night conditions. The results presented in this study will improve the knowledge concerning wood/PCM composites performance and concerning PCMs issues in cold climates. This study exposes the potential of wood-based panels integrated with PCM to achieve winter energy savings and enhance the summer thermal comfort of a timber-frame building, for a cold Canadian climate. [ABSTRACT FROM AUTHOR]

Energy consumption in new buildings can be reduced at the design stage. This study optimizes the ventilation system design of a new residential building located in a warm climate (Southern Italy). Different system options of horizontal air-ground heat exchangers (HAGHEs), also called earth-to-air heat exchangers (EAHX), have been considered to search for the optimal configuration. The thermal behaviour of the obtained configurations has been modelled by the dynamic simulation software TRNSYS 17. The pipe numbers, the air flow rate, and the soil thermal conductivity are among the simulated building components. For each of them, different design options have been analysed to study how each parameter impacts the building thermal behaviour in winter and summer. The operative air temperature (TOP) has been evaluated inside the building prototype to investigate the indoor comfort. The paper demonstrates that HAGHEs permit to assure a suitable indoor climatization if the building envelope is optimized for a warm area. These conditions require high values of heat storage capacity to keep under control the internal temperature fluctuations, especially in summer. The paper confirms the importance of geothermal systems and design optimization to increase energy savings. [ABSTRACT FROM AUTHOR]

To date, most of the indoor environment control is based on the dry-bulb air temperature, which is one of the simplified control methods having the limitation to truly represent the thermal comfort of individual occupants. A variety of factors affect the thermal comfort such as dry-bulb air temperature, humidity, air movement, radiation, clothing insulation, and metabolic activity level. In this circumstance, this study investigated the effects of considering hourly metabolic rate variations for predicted mean vote (PMV) control on the actual thermal load, energy usage, and life cycle cost (LCC). The case adopting PMV control taking the hourly metabolic rate into account was comparatively analyzed against the conventional dry-bulb air temperature control, using a detailed simulation technique after the validation process. As a result, when the activity state of the occupant is house cleaning in the summer, the indoor temperature decreases rapidly due to the high amount of activity. It requires a temperature that is 11.7 °C and 9.7 °C lower than the conventional dry-bulb air temperature control method, respectively, and generally forms a higher indoor air temperature than the conventional control method after 7 p.m. This means the difference in temperature to satisfy the comfort of the occupant according to the amount of activity, and during winter as opposed to summer, was found to form a lower indoor air temperature than the conventional temperature control. In case of annual boiler gas consumption, PMV control showed 7.3% less energy consumption than the dry-bulb air temperature control and showed 28.8% less energy consumption than the dry-bulb air temperature control for annual cooling electricity consumption. Considering the cooling and heating energy reduction rate and the initial installation cost of measuring equipment for real-time metabolic rate and PMV measurement, a payback period of approximately 4.15 years was required. [ABSTRACT FROM AUTHOR]